Re: Falling off the wagon

From a previous discussion (look under "wagon" in the discussion archives):

Various language sites state that The "wagon" in "on the wagon" refers to a fixture of America's past, the water wagon. Before roads were routinely paved, municipalities would dispatch horse-drawn water wagons to spray the streets in order to prevent the clouds of dust that traffic would otherwise cause. Anyone who had sworn abstinence from alcohol (and would presumably be drinking largely water from then on) was said to have "climbed aboard the water wagon," later shortened to "on the wagon."